Bug 205744 – Make text track loading set same-origin fallback flag

• Component: New Bugs
• Status: RESOLVED INVALID

[Rob Buis]

Make text track loading set same-origin fallback flag:
https://html.spec.whatwg.org/multipage/media.html#sourcing-out-of-band-text-tracks:create-a-potential-cors-request

[Rob Buis]

Created attachment 386706 [details]
Patch

[Rob Buis]

Comment on attachment 386706 [details]
Patch

This is the second and final part of the split mentioned in https://bugs.webkit.org/show_bug.cgi?id=205326.

[WebKit Commit Bot]

Comment on attachment 386706 [details]
Patch

Clearing flags on attachment: 386706

Committed r254031: <https://trac.webkit.org/changeset/254031>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.

[Radar WebKit Bug Importer]

<rdar://problem/58314610>

[Jer Noble]

Reopening as this patch caused a regression where videos on jw.org fail to show subtitles.

[Jer Noble]

jw.org has captions hosted on Akamai where the .vtt file has CORS headers but the .mp4 file does not. So captions work if `crossorigin=anonymous` is added, but that breaks video rendering.

Other browsers play captions fine without the `crossorigin` attribute, and there does not seem to be WPT tests that verify behavior for this scenario (!same origin, no-cors, headers present). Since this caused behavior regressions in the wild, and other browsers have not implemented this same behavior, we're reverting this on trunk for now.

[Rob Buis]

@Anne I implemented [1] but it seems to cause regressions in the wild, see comment 7. Do you know whether mozilla implemented this? Should the spec be changed?

[1] https://html.spec.whatwg.org/multipage/media.html#sourcing-out-of-band-text-tracks:create-a-potential-cors-request

[Anne van Kesteren]

I guess other browsers do not use "same-origin" as the fallback and rather use "cors" always? And let credentials mode depend on the media element? It seems this is the only case where we pass the same-origin fallback flag and it might not be well tested.

I do hope they all enforce CORS as there would be a security problem otherwise.

`html/semantics/embedded-content/media-elements/track/track-element/track-data-url.html` does not really seem to test this as data URLs are considered same-origin. That does seem like a useful template to be able to add some cross-origin tests, though testing the credentials part might require some server-side logic as well.

I filed https://github.com/whatwg/html/issues/6267 to track this standards-wise.

[youenn fablet]

I validated Chrome is using same origin as default.
Some time has passed and identified breaking websites have been updated.
Let's try to reland this behavior in https://bugs.webkit.org/show_bug.cgi?id=239381.